ends_with

ends_with(text, case_sensitive=False)

Select columns that end with specified text.

Many validation methods have a columns= argument that can be used to specify the columns for validation (e.g., col_vals_gt(), col_vals_regex(), etc.). The ends_with() selector function can be used to select one or more columns that end with some specified text. So if the set of table columns consists of

[first_name, last_name, age, address]

and you want to validate columns that end with "name", you can use columns=ends_with("name"). This will select the first_name and last_name columns.

There will be a validation step created for every resolved column. Note that if there aren’t any columns resolved from using ends_with() (or any other expression using selector functions), the validation step will fail to be evaluated during the interrogation process. Such a failure to evaluate will be reported in the validation results but it won’t affect the interrogation process overall (i.e., the process won’t be halted).

Parameters

text : str

The text that the column name should end with.

case_sensitive : bool = False

Whether column names should be treated as case-sensitive. The default is False.

Returns

: EndsWith

An EndsWith object, which can be used to select columns that end with the specified text.

Relevant Validation Methods where ends_with() can be Used

This selector function can be used in the columns= argument of the following validation methods:

• col_vals_gt()
• col_vals_lt()
• col_vals_ge()
• col_vals_le()
• col_vals_eq()
• col_vals_ne()
• col_vals_between()
• col_vals_outside()
• col_vals_in_set()
• col_vals_not_in_set()
• col_vals_null()
• col_vals_not_null()
• col_vals_regex()
• col_exists()

The ends_with() selector function doesn’t need to be used in isolation. Read the next section for information on how to compose it with other column selectors for more refined ways to select columns.

Additional Flexibilty through Composition with Other Column Selectors

The ends_with() function can be composed with other column selectors to create fine-grained column selections. For example, to select columns that end with "e" and start with "a", you can use the ends_with() and starts_with() functions together. The only condition is that the expressions are wrapped in the col() function, like this:

col(ends_with("e") & starts_with("a"))

There are four operators that can be used to compose column selectors:

• & (and)
• | (or)
• - (difference)
• ~ (not)

The & operator is used to select columns that satisfy both conditions. The | operator is used to select columns that satisfy either condition. The - operator is used to select columns that satisfy the first condition but not the second. The ~ operator is used to select columns that don’t satisfy the condition. As many selector functions can be used as needed and the operators can be combined to create complex column selection criteria (parentheses can be used to group conditions and control the order of evaluation).

Examples

Suppose we have a table with columns name, 2021_pay, 2022_pay, and person_id and we’d like to validate that the values in columns that end with "pay" are greater than 10. We can use the ends_with() column selector function to specify the columns that end with "pay" as the columns to validate.

import pointblank as pb
import polars as pl

tbl = pl.DataFrame(
    {
        "name": ["Alice", "Bob", "Charlie"],
        "2021_pay": [16.32, 16.25, 15.75],
        "2022_pay": [18.62, 16.95, 18.25],
        "person_id": ["A123", "B456", "C789"],
    }
)

validation = (
    pb.Validate(data=tbl)
    .col_vals_gt(columns=pb.ends_with("pay"), value=10)
    .interrogate()
)

validation

		STEP	COLUMNS	VALUES	TBL	EVAL	UNITS	PASS	FAIL	W	S	N	EXT
#4CA64C	1	col_vals_gt()	2021_pay	10		✓	3	3 1.00	0 0.00	—	—	—	—
#4CA64C	2	col_vals_gt()	2022_pay	10		✓	3	3 1.00	0 0.00	—	—	—	—

From the results of the validation table we get two validation steps, one for 2021_pay and one for 2022_pay. The values in both columns were all greater than 10.

We can also use the ends_with() function in combination with other column selectors (within col()) to create more complex column selection criteria (i.e., to select columns that satisfy multiple conditions). For example, to select columns that end with "pay" and match the text "2023" or "2024", we can use the & operator to combine column selectors.

tbl = pl.DataFrame(
    {
        "name": ["Alice", "Bob", "Charlie"],
        "2022_hours": [160, 180, 160],
        "2023_hours": [182, 168, 175],
        "2024_hours": [200, 165, 190],
        "2022_pay": [18.62, 16.95, 18.25],
        "2023_pay": [19.29, 17.75, 18.35],
        "2024_pay": [20.73, 18.35, 20.10],
    }
)

validation = (
    pb.Validate(data=tbl)
    .col_vals_gt(
        columns=pb.col(pb.ends_with("pay") & pb.matches("2023|2024")),
        value=10
    )
    .interrogate()
)

validation

		STEP	COLUMNS	VALUES	TBL	EVAL	UNITS	PASS	FAIL	W	S	N	EXT
#4CA64C	1	col_vals_gt()	2023_pay	10		✓	3	3 1.00	0 0.00	—	—	—	—
#4CA64C	2	col_vals_gt()	2024_pay	10		✓	3	3 1.00	0 0.00	—	—	—	—

From the results of the validation table we get two validation steps, one for 2023_pay and one for 2024_pay.